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ObjectivesThere are indications that the COVID-19 pandemic has had a profound negative effect on psychological well-being. Here, we investigated this hypothesis using longitudinal data from a large global cohort of runners, providing unprecedented leverage for understanding how the temporal development in the pandemic pressure relates to well-being across countries.DesignProspective cohort study.SettingGlobal.ParticipantsWe used data from the worldwide Garmin-RUNSAFE cohort that recruited runners with a Garmin Connect account, which is used for storing running activities tracked by a Garmin device. A total of 7808 Garmin Connect users from 86 countries participated.Primary and secondary outcome measuresFrom 1 August 2019 (prepandemic) to 31 December 2020, participants completed surveys every second week that included the five-item WHO Well-Being Index (WHO-5). Pandemic pressure was proxied by the number of COVID-19-related deaths per country, retrieved from the Coronavirus Resource Centre at Johns Hopkins University. Panel data regression including individual- and time-fixed effects was used to study the association between country-level COVID-19-related deaths over the past 14 days and individual-level self-reported well-being over the past 14 days.ResultsThe 7808 participants completed a total of 125 409 WHO-5 records over the study period. We found a statistically significant inverse relationship between the number of COVID-19-related deaths and the level of psychological well-being—independent of running activity and running injuries (a reduction of 1.42 WHO-5 points per COVID-19-related death per 10 000 individuals, pConclusionsThis study suggests that the COVID-19 pandemic has had a negative effect on the psychological well-being of the affected populations, which is concerning from a global mental health perspective.

Background: Adiposity increases endometrial cancer risk, possibly through inflammation, hyperinsulinemia, and increasing estrogens. We aimed to quantify the mediating effects of adiponectin (anti-inflammatory adipocytokine); IL6, IL1-receptor antagonist, TNF receptor 1 and 2, and C-reactive protein (inflammatory status biomarkers); C-peptide (hyperinsulinemia biomarker); and free estradiol and estrone (estrogen biomarkers) in the adiposity–endometrial cancer link in postmenopausal women. Methods: We used data from a case–control study within the European Prospective Investigation into Cancer and Nutrition (EPIC). Eligible women did not have cancer, hysterectomy, and diabetes; did not use oral contraceptives or hormone therapy; and were postmenopausal at recruitment. Mediating pathways from adiposity to endometrial cancer were investigated by estimating natural indirect (NIE) and direct (NDE) effects using sequential mediation analysis. Results: The study included 163 cases and 306 controls. The adjusted OR for endometrial cancer for body mass index (BMI) ≥30 versus ≥18.5− Conclusions: Reduced adiponectin and increased inflammatory biomarkers, C-peptide, and estrogens mediated approximately 70% of increased odds of endometrial cancer in women with obesity versus normal weight. Impact: If replicated, these results could have implications for identifying targets for intervention to reduce endometrial cancer risk in women with obesity.

INTRODUCTION: Based on survey data from September 2021, we recently reported that an estimated 90% (weighted total) of vaccinated (completed or scheduled) adult Danes were also willing to receive a COVID-19 booster vaccine, once offered. This survey was, however, fielded before booster vaccination was recommended to the general adult population in Denmark, which may have resulted in an underestimation of booster vaccine willingness. Therefore, we conducted a follow-up survey targeting the same individuals.METHODS: The follow-up survey wave was fielded in December 2021 using the same methods as in the September 2021 wave. Using data from participants responding to both survey waves, we compared COVID-19 booster vaccine willingness between the waves by means of paired t-test.RESULTS: A total of 1,429 invitees (58%) responded to the follow-up survey. Among those, 1,324 (93%) had also responded to the initial survey on COVID-19 booster vaccine willingness. At follow-up, among the 95% reporting to be vaccinated or that COVID-19 vaccination was scheduled, a weighted proportion of 95% indicated that they were willing to receive the booster vaccine once offered. Booster vaccine willingness at follow-up (December 2021) had statistically significantly increased (p less-than 0.001) compared with the initial survey (September 2021).CONCLUSIONS: Almost all of the COVID-19-vaccinated Danes seem willing to receive a booster dose of the vaccine, which bodes very well for the COVID-19 immunisation state in Denmark.FUNDING: The study was funded by a grant from the Novo Nordisk Foundation.TRIAL REGISTRATION: not relevant.

As the protection from the COVID-19 vaccines diminishes over time, health authorities are currently considering how to maintain immunity by means of vaccine booster doses. In a recent survey, we investigated COVID-19 booster vaccine willingness among Danes, a population with a high acceptance of the initial round of COVID-19 vaccination.The data were derived from the sixth wave of the longitudinal COVID-19 Consequences Denmark Panel Survey 2020, which included questions on booster vaccine willingness. The data from the respondents were primarily analysed using descriptive statistics. The association between age, gender, level of education, region, type of received vaccine and booster vaccine willingness was analysed using multivariate logistic regression.Among those reporting to be vaccinated against COVID-19 or that their vaccination was scheduled, a weighted total of 90% indicated that they were willing to receive the booster vaccine, if/once offered. The only characteristic associated with booster vaccine willingness at the set level of statistical significance (0.05) was age (increased willingness with age; adjusted odds ratio per year: 1.04, 95% confidence interval: 1.02-1.06).The willingness to receive a booster dose of a COVID-19 vaccine is high among Danes. If health authorities decide to offer COVID-19 booster vaccines to the young, they may consider providing specific information targeted at this population to increase uptake.The Novo Nordisk Foundation.not relevant.

We aimed to investigate whether higher light intensity in the morning is associated with better nocturnal sleep quality and whether higher light intensities in the evening or night have the opposite effect. Light intensity was recorded for 7 consecutive days across the year among 317 indoor and outdoor daytime workers in Denmark (55-56° N) equipped with a personal light recorder. Participants reported sleep quality after each nocturnal sleep. Sleep quality was measured using three parameters; disturbed sleep index, awakening index, and sleep onset latency. Associations between increasing light intensities and sleep quality were analyzed using mixed effects models with participant identity as a random effect. Overall, neither white nor blue light intensities during morning, evening, or night were associated with sleep quality, awakening, or sleep onset latency of the subsequent nocturnal sleep. However, secondary analyses suggested that artificial light during the morning and day contrary to solar light may increase vulnerability to evening light exposure. Altogether, we were not able to confirm that higher morning light intensity significantly improves self-reported sleep quality or that higher evening or night light intensities impair self-reported sleep quality at exposure levels encountered during daily life in a working population in Denmark. This suggests that light intensities alone are not important for sleep quality to a degree that it is distinguishable from other important parameters in daily life settings.

Background Even though in situ breast cancer (BCIS) accounts for a large proportion of the breast cancers diagnosed, few studies have investigated potential risk factors for BCIS. Their results suggest that some established risk factors for invasive breast cancer have a similar impact on BCIS risk, but large population-based studies on lifestyle factors and BCIS risk are lacking. Thus, we investigated the association between lifestyle and BCIS risk within the European Prospective Investigation into Cancer and Nutrition cohort. Methods Lifestyle was operationalized by a score reflecting the adherence to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) cancer prevention recommendations. The recommendations utilized in these analyses were the ones pertinent to healthy body weight, physical activity, consumption of plant-based foods, energy-dense foods, red and processed meat, and sugary drinks and alcohol, as well as the recommendation on breastfeeding. Cox proportional hazards regression was used to assess the association between lifestyle score and BCIS risk. The results were presented as hazard ratios (HR) and corresponding 95% confidence intervals (CI). Results After an overall median follow-up time of 14.9 years, 1277 BCIS cases were diagnosed. Greater adherence to the WCRF/AICR cancer prevention recommendations was not associated with BCIS risk (HR = 0.98, 95% CI 0.93–1.03; per one unit of increase; multivariable model). An inverse association between the lifestyle score and BCIS risk was observed in study centers, where participants were recruited mainly via mammographic screening and attended additional screening throughout follow-up (HR = 0.85, 95% CI 0.73–0.99), but not in the remaining ones (HR = 0.99, 95% CI 0.94–1.05). Conclusions While we did not observe an overall association between lifestyle and BCIS risk, our results indicate that lifestyle is associated with BCIS risk among women recruited via screening programs and with regular screening participation. This suggests that a true inverse association between lifestyle habits and BCIS risk in the overall cohort may have been masked by a lack of information on screening attendance. The potential inverse association between lifestyle and BCIS risk in our analyses is consistent with the inverse associations between lifestyle scores and breast cancer risk reported from previous studies.

Objective To assess light exposure during days with indoor, outdoor, and night work and days off work. Methods Light intensity was continuously recorded for 7 days across the year among indoor (n = 170), outdoor (n = 151), and night workers (n = 188) in Denmark (55–56°N) equipped with a personal light recorder. White light intensity, duration above 80, 1000, and 2500 lux, and proportion of red, green, and blue light was depicted by time of the day and season for work days and days off work. Results Indoor workers’ average light exposure only intermittently exceeded 1000 lux during daytime working hours in summer and never in winter. During daytime working hours, most outdoor workers exceeded 2500 lux in summer and 1000 lux in winter. Night workers spent on average 10–50 min >80 lux when working night shifts. During days off work, indoor and night workers were exposed to higher light intensities than during work days and few differences were seen between indoor, outdoor, and night workers. The spectral composition of light was similar for indoor, outdoor, and night workers during days at and off work. Conclusion The night workers of this study were during night hours on average exposed for a limited time to light intensities expected to suppress melatonin. The indoor workers were exposed to light levels during daylight hours that may reduce general well-being and mood, especially in winter. Outdoor workers were during summer daylight hours exposed to light levels comparable to those used for the treatment of depression.

High daytime light levels may reduce the risk of affective disorders. Outdoor workers are during daytime exposed to much higher light intensities than indoor workers. A way to study daytime light exposure and disease on a large scale is by use of a general population job exposure matrix (JEM) combined with national employment and health data. The objective of this study was to develop a JEM applicable for epidemiological studies of exposure response between daytime light exposure, affective disorders, and other health effects by combining expert scores and light measurements. We measured light intensity during daytime work hours 06:00–17:59 for 1–7 days with Philips Actiwatch Spectrum® light recorders (Actiwatch) among 695 workers representing 71 different jobs. Jobs were coded into DISCO-88, the Danish version of the International Standard Classification of Occupations 1988. Daytime light measurements were collected all year round in Denmark (55–56°N). Arithmetic mean white light intensity (lux) was calculated for each hour of observation (n = 15,272), natural log-transformed, and used as the dependent variable in mixed effects linear regression models. Three experts rated probability and duration of outdoor work for all 372 jobs within DISCO-88. Their ratings were used to construct an expert score that was included together with month of the year and hour of the day as fixed effects in the model. Job, industry nested within job, and worker were included as random effects. The model estimated daytime light intensity levels specific for hour of the day and month of the year for all jobs with a DISCO-88 code in Denmark. The fixed effects explained 37% of the total variance: 83% of the between-jobs variance, 57% of the between industries nested in jobs variance, 43% of the between-workers variance, and 15% of the within-worker variance. Modeled daytime light intensity showed a monotonic increase with increasing expert score and a 30-fold ratio between the highest and lowest exposed jobs. Building construction laborers were based on the JEM estimates among the highest and medical equipment operators among the lowest exposed. This is the first quantitative JEM of daytime light exposure and will be used in epidemiological studies of affective disorders and other health effects potentially associated with light exposure.

Objectives: The objective was to examine if night shift work is a short-term risk factor for breast cancer, including combined estrogen receptor (ER) and human epidermal growth factor 2 (HER2) breast cancer subtypes. Methods: The cohort comprised 155 540 public sector female workers in Denmark who were followed from 2007-2012. Day-to-day work-hour information was available from payroll registers and 1245 incident cases of breast cancer were identified in national cancer registries together with receptor subtype information. Results: A rate ratio (RR) of 0.90 [95% confidence interval (95% CI) 0.80-1.01] was observed for workers ever working night shifts during the follow-up period compared with workers only working day shifts after adjustment for age, age at first child, parity, family history of breast or ovarian cancer, sex hormones, medications related to alcoholism, family educational level, mammography screening, and other potential confounders. Comparable results were seen for the inception population of employees with first recorded employment after 2007. Modestly increased RR were suggested for breast cancer subtypes characterized by a positive HER2 status irrespective of ER status. Conclusions: These findings do not support an overall short-term effect of night shift work on breast cancer risk. Future studies should explore further the impact of HER2 status.

Objectives The aim of this study was to examine blood concentrations of 25-hydroxyvitamin D (25OHD) and parathyroid hormone (PTH) among indoor, outdoor, permanent and rotating night workers and the association with hours spent outdoors on and off work days. Methods Blood samples were collected from 425 workers (162 indoor, 112 outdoor, 118 rotating night and 33 permanent night workers) throughout all seasons. Serum concentrations of 25-hydroxyvitamin D (25OHD) and parathyroid hormone (PTH) were analyzed by isotope dilution liquid chromatography-tandem mass spectrometry (LC MS/MS) and an automated immune analyzer, respectively. Personal light exposure levels were continuously recorded and used to estimate hours spent outdoors (all workers). Results Permanent night workers had 25.3% (95% CI 11.9–36.6) lower 25OHD concentration, 4.55 (95% CI 1.39–14.94) higher odds of vitamin D insufficiency (

Objective We aimed to examine the effects of night work on salivary melatonin concentrations during and subsequent to night work and the mediating role of light. Methods We included 254 day workers and 87 night workers that were followed during 322 work days and 301 days off work. Each day was defined as the 24 hour period starting from the beginning of a night shift or awakening in mornings with daytime work and days off. Light levels were recorded and synchronised with diary information on start and end of sleep and work. On average, participants provided four saliva samples per day, and these were analysed for melatonin concentration. Differences between day and night workers on work days and days off were assessed with multilevel regression models with melatonin concentrations as outcome. All models were stratified or adjusted by time of the day. For light exposure, we estimated the total, direct, and indirect effects of night work on melatonin concentrations obtaining 95% confidence intervals trough bootstrapping. Results On work days, night workers showed 16.5% (95% CI 0.2; 30.5) lower salivary melatonin concentration compared with day workers. Light exposure seemed to mediate about 40% of the melatonin suppression seen during night, but no mediating effect of light was seen during day time. On days off, we observed no difference in melatonin concentration between day and night workers. Conclusion These findings are in accordance with a transient and partly light mediated effect of night work on melatonin concentration.

We aimed to examine the effects of night work on salivary melatonin concentration during and subsequent to night work and the mediating role of light. We included 254 day workers and 87 night workers who were followed during 322 work days and 301 days off work. Each day was defined as the 24 hour period starting from the beginning of a night shift or from waking in the mornings with day work and days off. Light levels were recorded and synchronized with diary information (start and end of sleep and work). On average, participants provided four saliva samples per day, and these were analyzed for melatonin concentration by liquid chromatography tandem mass spectrometry (LC-MS/MS). Differences between day and night workers on work days and days off were assessed with multilevel regression models with melatonin concentration as the primary outcome. All models were stratified or adjusted by time of day. For light exposure, we estimated the total, direct and indirect effects of night work on melatonin concentrations obtaining 95% confidence intervals through bootstrapping. On work days, night workers showed 15% lower salivary melatonin concentrations compared with day workers (-15.0%; 95% CI: -31.4%; 5.2%). During the night, light exposure mediated a melatonin suppression of approximately 6% (-5.9%, 95% CI: -10.2%; -1.5%). No mediating effect of light was seen during the day time. On days off, we observed no difference in melatonin concentrations between day and night workers. These findings are in accordance with a transient and partly light-mediated effect of night work on melatonin production.

We thank Dr Richard Stevens for his comments (1) on our recent article that showed no increased risk of breast cancer following recent night shift work when compared with recent day shift work (2). This finding was based on linkage of day-by-day information on working hours and breast cancer incidence data. Results are thus less likely to have been biased by differential misclassification than findings from earlier studies relying on self-report (3). We defined a night shift as ≥3 hours of work between 24:00–05:00 hours and a day shift as ≥3 hours work between 6:00–20:00 hours. This day shift definition did not exclude shifts starting before 05:00 or ending after 24:00 hours. However, this affected only 0.02% and 0.3% of all day shifts, respectively. This diminutive misclassification, that is expected to be non-differential, can hardly explain our negative findings. It is suggested that shifts that begin after 07:00 and end before 18:00 would constitute a more sensible baseline comparison group. Since the biological mechanism is not certain, it is not obvious to us if this will be a more appropriate reference than the present. However, we agree that future studies should test how different definitions of shifts affect the risk of breast cancer, which will be possible using this type of data. We only had information on working hours from 2007 and onwards, and night shift work prior to 2007 could have confounded our analyses towards no effect but only if inversely associated with night shift work in 2007 or later. We find this unlikely. Left truncation could also have biased findings towards the null. We therefore supplemented analyses of the total study population with analyses of the one-third of the population with first recorded employment in 2008 or later (the inception population). Even if the mean age was 35.5 years – and many undoubtedly had been working (with and without night shifts) prior to 2008 – this population should be less affected by such selection bias, but we observed similar risk estimates as for the total study population. Taken together, we find that our study provides rather robust evidence of no short-term breast cancer risk following recent night shift work. It must, however, be stressed that data did not allow assessment of a possible long-term risk. Reference 1. Stevens R. Letter ref. Vitisen et al: “Short-term effects of night shift work on breast cancer risk: a cohort study of payroll data”. Scand J Work Environ Health. 2017;43(1):95. http://dx.doi.org/10.5271/sjweh.3607 2. Vistisen HT, Garde AH, Frydenberg M, Christiansen P, Hansen AM, Hansen J, Bonde JP, Kolstad HA. Short-term effects of night shift work on breast cancer risk: A cohort study of payroll data. Scand J Work Environ Health. 2017;43(1):59–67. http://dx.doi.org/10.5271/sjweh.3603. 3. Ijaz S, Verbeek J, Seidler A, Lindbohm ML, Ojajarvi A, Orsini N, Costa G, Neuvonen K. Night-shift work and breast cancer--a systematic review and meta-analysis. Scand J Work Environ Health. 2013 Sep 1;39(5):431-47. http://dx.doi.org/10.5271/sjweh.3371

Objective Exposure to high levels of light during night and low levels during day time may have adverse health effects. Our aim is to characterise light exposure levels in night shift, outdoor, and indoor day workers. Methods We recruited 535 night shift, outdoor, and indoor workers that for seven days wore a Phillips Actiwatch Spectrum on the upper dominant arm during days of work and days off. This device records red, green, blue and white light level every minute. Participants also filled in a diary on work and sleep hours that was synchronised with illuminance- calibrated white light exposure recordings (lux). Results A total of 3.7 million one-minute lux recordings were obtained. They were highly right skewed with work day mean and medians of 968 and 33 lux, respectively. Night shift workers showed a night time mean level of 20 lux, which was fourfold the levels seen in indoor (6 lux) and outdoor workers (4 lux) during night time. However, 24 h mean levels during workdays were lower in these mainly rotating night shift workers (572 lux) than in outdoor (1449 lux) and indoor workers (996 lux). Indoor workers compensated for low work time exposure by higher off work illuminance levels, while this was not the case for the night and outdoor workers. Discussion This study provides illuminance levels during work, leisure and sleep that may link laboratory and epidemiological findings. Account has to be taken that periods where the measuring devise was not used was excluded in the study. Conclusion Night shift workers experience higher levels of illuminance during night shifts but lover overall levels during work days compared to indoor and outdoor workers. Both may affect circadian rhythm. Outdoor workers experience illuminance levels during the day that has shown to ease depression in experimental studies.

The 2014 workshop on "Co-ordination of research on working hours and health in the Nordic countries" was held at the Finnish Institute of Occupational Health on the 23rd-24th October 2014. The over ...

This report presents a summary of a workshop entitled "Co-ordination of research on working hours and health in the Nordic countries". The workshop was held at the National Research Centre for the ...

OBJECTIVES: Experimental evidence suggest a short-term effect of light at night on breast cancer oncogenesis. We studied the short-term effect of night work on breast cancer occurence.METHOD: We established a large, national cohort of employees in the public health care sector with a high prevalence of night shift work and with detailed data regarding occupational title and date and hour for beginning and end of every work duty: The Danish Working Hour Database (DWHD). DWHD encompasses payroll data as of 2007 and is updated on an annual basis. For this analysis we defined night work as at least 3 h of work between midnight and 05:00. From national cancer registers we retrieved information about breast cancer diagnosis for all female workers and their relatives. Reproductive history, hormone medications, attendance in mammography screening, and vital status were obtained from other national health registries.RESULTS: The 6-year follow up from 2007 to 2012 included 169.011 women of which 98.297 (58%) had ever worked nights during the follow up. A total of1.281 breast cancer cases occurred within the study population. 846 cases occurred among women never worked nights and 435 cases among women ever worked nights.CONCLUSIONS: Internal risk assessment of this dataset that includes alternative exposure metrics based on day-to-day night work exposure information will be presented.